Underwater in situ placement of concrete

ABSTRACT

A flexible container filled with dry concrete which will quickly set upon the addition of moisture. Because of the container&#39;&#39;s flexibility, it may be formed into any desired container to fit available space after which moisture is added.

O iimted States Patent 1 [111 3,745,775 Kahn [45] July 17, 1973UNDERWATER IN SITU PLACEMENT 0F [56] References Cited CONCRETE UNITEDSTATES PATENTS [75] Inventor: Lawrence F. Kahn, Ann Arbor, 3,388,5096/1968 Mora 52/2 MiCh. 511,472 12/1893 Sumovski.. 52/2 1,421,857 7 1922St 61 46 [73] Assignee: The United States of America as ore representedby the Secretary of th Primary Examiner-Jacob Shapiro Navy, Washington,DC. Attorney-Richard S. Sciascia, Q. B. Warner and J. 221 Filed: Nov.22, 1971 Amand v 211 App]. No.: 201,016 [571 ABSTRACT A flexiblecontainer filled with dry concrete which will quickly set upon theaddition of moisture. Because of [2%] 61/46, 615%:5/83 tha containefsflexibility it may be formed into any E d 63 59 sired container to fitavailable space after which mois- 1e 0 care 61/,30 301,52, ture is added5 Claims, 6 Drawing Figures UNDERWATER IN SITU PLACEMENT OF CONCRETESTATEMENT OF GOVERNMENT INTEREST The invention described herein may bemanufactured and used by or for the Government of the United States ofAmerica for governmental purposes without the payment of any royaltiesthereon or therefor.

' BACKGROUND OF THE INVENTION Current techniques for the subaqueousplacement of concrete and their disadvantages are as follows:

The tremie method is a common technique for placing fresh concreteunderwater. Concrete is poured from the surface through a hollow tubeinto a submerged form. Disadvantages of the method are that l) pouringis controlled from the surface, (2) a separate formwork must beconstructed and placed underwater, (3) the method is limited in thedepth to which concrete may be poured, (4) the sea state must berelatively calm, and (5) strict control must be maintained to avoidsegregation of the concrete. A second method of placing freshly mixedconcrete underwater is to use dump buckets. A bucket filled withconcrete is lowered on a line into submerged forms, the concrete isdumped. The disadvantages of this method are the same as those of thetremie method. Further disadvantages include fouling of the guide linesfor controlling the bucket, non-continuous pouring, setting of theconcrete before it is placed, and leeching of the cement from theconcrete.

A third method of underwater concreting is preplaced aggregate concrete,a process known as Intrusion Prepakt concrete. Aggregate is placed intosubmerged form, grout is then pumped into the forms either through hosesattached to the forms or through pipes embedded in the aggregate. Thegrout fills the voids and displaces the water. Although prepacking hasadvantages over other methods, disadvantages of this method are that (I)a separate underwater form must be constructed and placed, (2 preplacingthe aggregate by bucket is time consuming, (3) the grout flow must beaccurately controlled, (4) the placement of aggregate and the groutingare dependent on the seat state, and (5) operations must be controlledfrom the surface.

A fourth technique is the Fabriform system which .consists of pumping aporous nylon-fabric form full of grout. Pumping pressures expel excesswater through the pores while a lower water/cement ratio grout remainsbehind. This technique is currently being used to line canals withconcrete. The principal disadvantage with this method is that it issurface controlled. In the deep ocean, accurate placement of theflexible bag by a surface ship would be difficult, and the grout must bepumped from the surface.

Using precast concrete elements underwater is an altemative to placingfreshly mixed concrete on the ocean floor. Even though precast elementsshow great promise for structural applications underwater, disadvantagesdo exist. The principal disadvantage of the precast element is that itdoes not conform to the ocean floor. Where the ocean floor is irregular,a foundation mat, overlay, or structure resting directly on the floorshould conform to the shape of the floor.

SUMMARY OF THE INVENTION The foregoing as well as other attendantdisadvantages have been overcome in the present invention by awaterproof flexible container filled with dry concrete which willquickly set upon the addition of moisture. The container is ofsubstantially neutral buoyancy so that it may readily be transported toan underwater location by a diver. Because it is not yet rigid it may bemolded and formed into a desired contour to fit the available space.After being fitted into place moisture is introduced, with or withoutagitation, and the bag contents quickly harden into a rigid monolithicblock of the shape previously imparted thereto. Moisture may be added inseveral ways as by bag puncture to admit ambient water, opening ofpassages ported into several portions of the bag, or release ofentrained moisture capsules.

Accordingly an object of this invention is to provide a flexiblecontainer filled with concrete which will rapidly set upon the additionof water. Another object of the invention is to provide a dry concretemodule which is neutrally buoyant for easy underwater emplacement.

A further object of the invention is to provide a simple, economical yetefficient arrangement wherein a dry concrete mix may be transported to asubaqueous position and water incorporated after the concrete has beenpositioned.

Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view of theinvention constructed in accordance with the present invention.

FIG. 2 is a schematic sectional view along the line 22 of FIG. 1.

FIG. 3 is a schematic sectional view similar to FIG. 2 showing a varieddesign of the invention to meet particular requirements.

FIG. 4 is a schematic sectional view similar to FIG. 2 illustrating amechanism for internal vibration.

FIG. 5 is a schematic sectional view similar to FIG. 2 showing the bagwith less than all sides being double walled.

FIG. 6 is a sectional view similar to FIG. 2 illustrating a keyingarrangement between adjacent bags.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2,there is indicated a bag I 10 having an inner wall I2 and an outer wallM which controlled by valves 28 provide gas and liquid access to innerwall compartment 16. Vents 30 with valves 32 also provide access betweenthe exterior and outer wall compartment 18.

In use the bag 10 is pressurized to a rigid state enclosing a baginterior chamber 20 by pumping a gas into compartments l6 and 18 throughvents 26 and 30 and by controlling valves 28 and 32. Such pressurizationcauses the bag walls 12 and 14 to become rigid and enclose a baginterior chamber 20.

The interior chamber 20 is filled with a dry concrete mixture blown intobag 10 through vent 22. The concrete mixture is so proportioned thatwhen ocean water is added to it, a high quality concrete is obtained. Inthe preferred embodiment, the porosity of the dry'mixture is sufficientto allow water to flow through without the need for internal or externalvibration. Other types of cement mixtures could be used in place of theconcrete mixture used in the preferred embodiment including quick setcement, water curing adhesives and the inclusion of reinforcingmaterials in the cement mixture.

The pressurized and rigid bag 10 filled with a dry concrete mixture-isneutrally buoyant when placed in the ocean and may be easily handled bydivers or work submersibles. The degree of initial buoyancy may bealtered as required by slight changes in design of the wall compartmentsl6 and 18.

Thus, when the rigid bag 10 filled with concrete mixture is placed onthe ocean surface in the area where it is to be used subaqueously, thevalves 32 are actuated which allow water to flow through vents 30 intowall compartment 18. This addition of water causes the bag 10 to becomenegatively buoyant. The bag 10 descents to the subaqueous site. It isstill rigid because valves 28 providing access to inner wall compartment16 through vents 26 have remained closed. However, once in itssubaqueous position, valve 24 is opened allowing sea water to flowthrough vent 22 thereby penetrating the dry concrete mixture. In timethe concrete cures and hardens after which the bag 10 and valves may beremoved if desired.

In another embodiment of the invention, vibrator fingers 34 may beincorporated into the bag 10 as shown in FIG. 4. A vibration generatoris attached to the fingers at the proper time, preferably when valve 24is actuated to allow sea water to enter vent 22 wetting the cementmixture therein, thereby permitting vibrator fingers 34 to agitate theconcrete.

As shown in FIG. all the sides of the bag need not be double walled iflower flexibility or less rigidity in the bag is required. Sufficientrigidity or stiffness is maintained to accurately form the concrete andthe buoyancy will remain neutral.

The ability to vary the shape of the bag 10 permits key connectionsbetween bags, one of which is illustrated in FIG. 6. Keying together ofmodules enables large areas of the ocean floor to be covered withconcrete for varying purposes such as foundations for large structuresand landing areas for submersibles. Other keying arrangements canobviously be used if desired including the use of drift pins. Othervarying shapes of bag 10 may obviously be used, one of which isillustrated in FIG. 3.

The use of sea water as a mixing agent for concrete is satisfactory inmost instances. However, there is some evidence that sea water having avery high concentration of chloride and sulfate ions may result in poorquality concrete if mixed therewith. To obviate such a condition, freshwater or water treated to remove the destructive ions may be placed inone of the wall compartments of bag 10 and then released as requiredinto the enclosed concrete.

It is clear that any type of valve or similar arrangement may be used tofill the various compartments and chambers in the several embodimentswithout changing the original concept of this invention.

Obviously, many modifications and variations of the present inventionare possible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

I claim:

1. A flexible device for the subaqueous emplacement of concretecomprising:

a bag having a double wall, said double wall forming attached'butseparate inner and outer wall compartments;

vents positioned in each of said inner and outer compartments, saidvents adapted to provide gas and liquid access from the exterior to theinterior thereof;

valves controlling the opening into said vents;

thus upon inflating the bag wall compartments, the

bag retains a form and is neutrally buoyant;

a dry concrete mix positioned in the bag chamber;

a bag vent extending through said double wall into said chamber of thebag and;

a bag vent valve controlling the opening in said bag vent;

said bag vent being opened after emplacement of the bag to permit waterto enter and mix with the cement material therein.

2. A flexible device having a dry concrete mix positioned therein anddesigned for the subaqueous emplacement of concrete comprising:

a bag having a double wall, said wall forming attached but separateinner and outer wall compartments;

means located in each of said inner and outer compartments to providecontrolled access from the exterior to the interior thereof;

thus upon inflating said bag wall compartments, the

bag retains a form and is neutrally buoyant;

bag venting means located in said bag double wall and adapted to providecontrolled access from the exterior to the interior of the chamber insaid bag;

said means positioned in said inner and outer compartments to providecontrolled access thereto and the bag venting means include.

vents located in each of said inner and outer compartments withcooperating valves to control the openings therein and;

a vent located in said double wall of the bag and extending into the bagchamber, said vent having a valve to control the opening therein;

thus when the bag is positioned at its underwater location said bagventing means is opened to allow water to mix with the dry concretetherein.

3. The device of claim 2 wherein the double wall having separate innerand outer compartments is present on less than all sides of said bag.

4. The device of claim 2 wherein:

a vibrator finger is incorporated into the chamber of said bag, saidvibrator finger adapted to be attached to a vibrator generator whenincreased mixing of the concrete mix and water is required.

5. The device of claim 2 wherein each flexible bag contains interlockingkey connections so as to permit adjacent bags to be keyed together overlarge expanses of the ocean floor.

* 3 t i i

1. A flexible device for the subaqueous emplacement of concretecomprising: a bag having a double wall, said double wall formingattached but separate inner and outer wall compartments; ventspositioned in each of said inner and outer compartments, said ventsadapted to provide gas and liquid access from the exterior to theinterior thereof; valves controlling the opening into said vents; thusupon inflating the bag wall compartments, the bag retains a form and isneutrally buoyant; a dry concrete mix positioned in the bag chamber; abag vent extending through said double wall into said chamber of the bagand; a bag vent valve controlling the opening in said bag vent; said bagvent being opened aFter emplacement of the bag to permit water to enterand mix with the cement material therein.
 2. A flexible device having adry concrete mix positioned therein and designed for the subaqueousemplacement of concrete comprising: a bag having a double wall, saidwall forming attached but separate inner and outer wall compartments;means located in each of said inner and outer compartments to providecontrolled access from the exterior to the interior thereof; thus uponinflating said bag wall compartments, the bag retains a form and isneutrally buoyant; bag venting means located in said bag double wall andadapted to provide controlled access from the exterior to the interiorof the chamber in said bag; said means positioned in said inner andouter compartments to provide controlled access thereto and the bagventing means include. vents located in each of said inner and outercompartments with cooperating valves to control the openings thereinand; a vent located in said double wall of the bag and extending intothe bag chamber, said vent having a valve to control the openingtherein; thus when the bag is positioned at its underwater location saidbag venting means is opened to allow water to mix with the dry concretetherein.
 3. The device of claim 2 wherein the double wall havingseparate inner and outer compartments is present on less than all sidesof said bag.
 4. The device of claim 2 wherein: a vibrator finger isincorporated into the chamber of said bag, said vibrator finger adaptedto be attached to a vibrator generator when increased mixing of theconcrete mix and water is required.
 5. The device of claim 2 whereineach flexible bag contains interlocking key connections so as to permitadjacent bags to be keyed together over large expanses of the oceanfloor.